The invention, for one, concerns a reactive set for producing a synthetic resin body used for anchoring fasteners in a base through employment of destructible multiple chamber cartridges. Specifically, the invention is geared to a specific combination of components of the reactive set for production of a synthetic resin body, a destructible multiple chamber cartridge for anchoring fasteners in a base, and an anchoring process where the multiple chamber cartridge contains the specific reactive set.
It has been known for a long time to use curable synthetic resins for the safe fastening of anchoring rods and similar devices in solid rock, masonry, concrete and similar materials. The starting components of the synthetic resin and synthetic resin hardener are separately brought to the point of fastening and mixed there by driving the fastener in. Thus, the formation of the cured synthetic resin body that glues the fastener to the base is initiated only when the fastener is contained in its final position.
The widespread popularity of this technique is attributable, among others, to the use of destructible cartridges which permit a convenient introduction of resin components and synthetic resin hardeners in boreholes for anchoring rods and, moreover, facilitate the storage, transport and dosing of the reactive starting materials of the synthetic resin body.
Cartridges containing reactive sets for the production of cured synthetic resin bodies were described already in the German patent publication 12 05 038, in conjunction with a process for the fastening of anchoring rods without spreader head in the anchored construction of mining spaces. Concerned there are glass or bakelite cartridges into whose charge from curable polyester or epoxy resin and similar or larger quantity by weight of quartz sand or meal a capsule is introduced that contains the hardener. According to this document, organic peroxides are used in conjunction with polyesters. In the case of preaccelerated epoxy resins, an amine hardener is used. Although cartridges with reaction sets of that type have been used for several years in the fastening technology, they are associated with considerable drawbacks. These consist in the slow curing of preaccelerated epoxy resins with amine hardeners so that, when a quick load bearing capability of the fastener is required, the glass cartridge and the anchoring rod need to be preheated to temperatures above 150.degree. C. With the peroxide-cured polyester resins it proves to be disadvantageous that they are insufficiently resistant to chemicals, specifically not resistant to alkali. Especially in a basic base this leads in the long run to a reduction of the mechanical properties of the synthetic resin body. Moreover, such cured polyester resins also display a relatively high water absorption, which in conjunction with metallic fasteners may cause corrosion problems.
To eliminate the disadvantages of such prior materials, the European patent application 0 150 555 (U.S. Pat. No. 4,729,696) suggested dual chamber cartridges where a fine-grained, natural or synthetic mineral filler, together with a vinyl ester epoxy resin on acrylate or methacrylate basis, is contained in the inner or outer chamber of a dual chamber cartridges constructed of two nested glass cylinders while the hardener--an organic peroxide--is contained in the respective other chamber. The peculiarity of cartridges according to the European patent application 0 150 555 consists in the fact that a reactive vinyl monomer is admixed to the resin component.
The synthetic resin substances according to the European patent application 0 150 555 represent a significant advancement over previously known resin compositions insofar as, for one, they cure faster than previously used epoxy resins and, for another, they are in terms of alkali resistance superior to the previously used polyester resins. Nonetheless, also the synthetic resin bodies which according to the recipe taught by the European patent application are obtained upon crushing the glass cartridges and curing of the components of the reaction set have considerable disadvantages: for one, such synthetic resin bodies do not represent a sufficiently effective diffusion barrier against reactive compounds, such as hydrochloric acid or diffusing water vapor. This relatively high permeability to low-molecular substances causes ultimately a reduction of the corrosion resistance of the metallic fastener. Another grave disadvantage of anchorings obtained with synthetic resin bodies according to the specification of the European patent application 0 150 555 is constituted by its mechanical performance. Under sustained load, synthetic resin bodies obtained in this way tend to soften. As a result of the resin matrix creepage caused thereby, a safe anchoring over longer periods of time cannot be guaranteed with such synthetic resin material under sustained load, due to the risk of fastener slippage. Thus, this resin type is unsuited for many applicational areas in construction where the fastener must safely withstand decades of tractive stress.
This disadvantage is amplified yet in that the somewhat satisfactory curing speed, as a result of which the fastener can be stressed a relatively short time thereafter, is caused by a high percentage of hardener component in the resin recipe. The high percentage of organic peroxide such as taught in the European patent application 0 150 555, for one, causes a quick curing of the synthetic resin mixture though, while on the other hand it has the undesirable side effect of promoting also the quick aging of the synthetic resin body. Given with the chemical changes which in the course of time reduce the adhesion of the resin to the surrounding base and to the fastener and adversely affect the inner structure and thus the strength of the synthetic resin substance itself (brittling) is another risk factor which makes the long term use problematic.
Disadvantageous, futhermore, is that a curing time of several days must still be allowed, despite a comparatively high curing speed at normal temperatures (25.degree. C.), and even elevated temperatures (35.degree. C.) require curing times in the range of hours, until the fastener can be subjected to load. For many practical purposes where cost intensive waiting periods are caused in that an anchored fastener cannot be subjected to load yet, the application of the teaching of the European patent application 0 150 555 is giving rise to problems.
Another negative aspect of the prior art is the dissatisfactory shelf life of the synthetic resin components in the cartridges, especially at elevated temperature.
The problem underlying the invention is to provide a reactive set, specifically for use in multiple chamber cartridges, for the production of a synthetic resin body that causes the anchoring of fasteners in the base and is characterized in that it produces after a short curing time highly loadable anchorings which remain consistently stable under mechanical sustained load, display a high resistance to acid and alkali, form an effective diffusion barrier to low-molecular compounds and possess an equally high adhesion to metals and natural and synthetic mineral materials and, when needed, can be so designed, without reducing their properties which are essential in practice, that a shelf life at elevated temperatures is given.